延长DF,作AM//BD交DF延长线于M,
《AFM=〈BFD(对顶角),
〈AMF=〈FDB(内错角相等),
△AMF∽ △BDF,
AF/BF=AM/BD,
AM=2*5/4=5/2,
〈AEM=〈CED(对顶角相等),
AE=CE,
〈MAE=〈ECD(内错角相等),
△AME≌△CED,(ASA)
∴CD=AM=5/2.
延长DF,作AM//BD交DF延长线于M,
《AFM=〈BFD(对顶角),
〈AMF=〈FDB(内错角相等),
△AMF∽ △BDF,
AF/BF=AM/BD,
AM=2*5/4=5/2,
〈AEM=〈CED(对顶角相等),
AE=CE,
〈MAE=〈ECD(内错角相等),
△AME≌△CED,(ASA)
∴CD=AM=5/2.